Calories, not cups
A cat's correct daily intake is a calorie figure driven by weight, age, activity and whether the cat is neutered - spaying and neutering lower energy needs, which is exactly when many cats start gaining on the same portions. Food labels carry feeding guides, and fresh subscriptions calculate portions from your cat's profile, but every guide is a starting point rather than a verdict. Two cats of identical weight can need meaningfully different amounts; the number gets tuned by watching the actual cat, which is the last section of this guide.
The free-feeding trap
Leaving a full bowl down all day suits a minority of naturally lean self-regulators and quietly overfeeds most everyone else - it's the single most common way indoor cats end up overweight, and excess weight is among the most common and most preventable health problems in cats. Measured meals - typically two or more per day - give you portion control, make appetite changes visible early (a meal-fed cat that skips dinner is telling you something a grazed bowl never would), and make multi-cat households manageable, since free-feeding also hides who's eating whose share.
Treats are part of the math
Treats, lickable tubes, and the tax your cat levies on your breakfast all count against the same daily calories, and they add up faster than intuition suggests for an animal this small. Common veterinary guidance keeps treats to a modest share of the day's intake - roughly a tenth is the figure often cited - with the main meals carrying the complete-and-balanced nutrition. If training or bonding involves lots of treats, shave the meals accordingly rather than stacking extras on top.
How to know you've got it right
Ignore the campaigning - many cats solicit food convincingly at any weight - and read the body instead, over weeks: ribs you can feel under a thin layer without seeing them, a visible waist from above, a belly that tucks rather than sways. Weight drifting up means trim portions; drifting down unexpectedly is a vet conversation, not just a bigger scoop. And if your cat needs to lose weight, do it only gradually and with your vet involved - crash-dieting a cat is genuinely dangerous, which is exactly why the portion question deserves this much care in the first place.